1. Field of Invention
This invention relates to the installation of registers and grilles used as air outlets or inlets in warm air heating, ventilating, and air conditioning systems, specifically to floor mounted registers.
2. Description of Prior Art
Heretofore, installers of heating, and air conditioning systems would install floor mounted registers in the following manner. A generally rectangular hole, somewhat larger than the register to be installed, would be cut through a wooden floor surface. Placed into this hole, from below, would be a duct fitting commonly refered to as a boot, generally pre-fabricated from a sheet material, having a first end of sufficient size and shape to allow insertion of the grille or register, and a second generally round end to allow connection to the air distribution system. After fastening the boot to the floor surface with screws or nails the register is inserted into the boot from above, being held in place by a combination of friction and gravity.
When using this method, the hole through the floor surface must be cut perfectly square and accurate. If the hole is cut too large, it will cause spaces, or gaps between the boot and flooring allowing air leakage between conditioned and unconditioned spaces, and allow undesirable lateral movement, and/or twisting of the register. Fasteners could be driven through the face of the register into the flooring, however they would be visible and unattractive, and could pose a hazard to a barefoot person.
If the hole is cut too small, or not perfectly square, the register will either not fit, or will have to be forced into the hole, causing binding of volume damper blades or other moving parts on the register.
When fastening the boot to the floor surface, one must exercise caution not to split the flooring material since this sometimes happens when nailing or screwing into the end grain of plywood or solid flooring. These fasteners must be driven in perfectly flush with the inner surface of the boot so they will not interfere with the insertion of the register.
This installation procedure generally requires two people, since one person must hold the boot into the hole from below the floor, to prevent it from falling out of the hole, while the second person fastens the boot to the flooring from above.
A duct connection flange described in U.S. Pat No. 4,566,724 to Arnoldt et al utilizes a protuberance arrangement that eliminates the need for external fasteners when connecting it to a duct, but requires full engagement of the duct before any fastening takes place. If the installer needs to reposition after partially engaging a corner or side of the duct, it may fall free of the flange if pressure is released. This is especially true when making a vertical connection, due to gravity. Also, because of its physical configuration this device would not fit into the hole from above the flooring. Therefore to use this device for the above application it would have to be fastened from below the floor making it cumbersome to install, and difficult to seal. Also, any device that creates a flange on the perimeter of the holes, underside could interfere with floor joists or framing members adjacent to the hole.
U.S. Pat. No. 5,472,380 to Sarazen, Jr. et al improves the original method by using a two piece snap together register which holds the register fast in the hole to prevent lateral, or twisting of the register after installation, without leaving any fasteners exposed from above. This invention however, does not make provisions for connection of the boot, but relies on creating an outwardly turned flange to be fastened to the underside of the floor surface. This requires overhead nailing which can be difficult in a confined space between floor joists as is commonly encountered in this situation. Also to achieve an airtight seal, would be difficult, since the underside of most flooring systems tends to be rough and have imperfections such as gaps in floorboards, and nails protruding from above.